Italian police said between 60 and 70 people were injured, some with severe burns, during the midday accident on the raised highway north of the city. The Carabinieri paramilitary police said some officers were injured by flying glass when windows in a nearby barracks burst.
Officials said they did not know yet what was in the truck’s tanks, but Italian news agency ANSA reported it was liquefied petroleum gas.
Videos of the blast site showed flames shooting up in the air, followed by a thick cloud of black smoke. Aerial photos showed a gaping hole in the highway next to the tanker.
Italian television Sky TG24 said flames from the first explosion set off secondary blasts in a new car lot below. It said some of the people injured were hit by flying glass from windows in nearby buildings.
Firefighters said the flames were extinguished several hours after the explosion, ANSA reported.
Authorities said a major highway interchange had been closed north of the city due to the accident. The interchange connects two highways linking northern Italy with the Adriatic coast.
Italy’s infrastructure and transport minister, Danilo Toninelli, said authorities were working to ensure traffic would be able to move smoothly “on such a critical stretch.”
In a separate accident in the southern Italian region of Puglia, 12 farm workers were killed Monday when the van they were traveling in overturned, ANSA reported.